How to Care for a Canadian Hemlock Bonsai

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The stately Canadian hemlock (Tsuga canadensis) grows in a slightly rounded, pyramidal shape and produces dark-green, needlelike foliage on limbs covered with furrowed, grayish-brown bark. In its mature form, this evergreen has a height range of 40 to 70 feet. Hardy in U.S. Department of Agriculture plant hardiness zones 4 through 8, the Canadian hemlock requires partial to full sunlight and regular moisture to thrive. Growing a Canadian hemlock as a bonsai requires a moderate amount of maintenance that when done correctly captures the tree's characteristics and form in a miniature specimen.

1

Place the Canadian hemlock bonsai plant in an area that receives at least three to five hours of morning sunlight and afternoon shade. Position the plant in an area that has constant air circulation but receives protection from strong winds.

2

Fill a watering can with 75- to 80-degree-Fahrenheit water. Touch the soil's surface in the Canadian hemlock bonsai's pot, or container, with your palm once or twice per day to test the soil for moisture. Water the plant only when the soil feels dry. Fill the container to the top with water from the watering can. Wait for the soil to absorb the water. Fill the container to the top a second time with water. Discard any water that collects in the pot's draining tray. Do not splash the foliage while watering the bonsai. Never let the soil dry out completely or become soggy.

3

Mix 3/4 teaspoon of 20-20-20 (nitrogen, phosphorus, potassium) liquid soluble fertilizer with 1 gallon of water in a watering can using a spoon. Stir the solution until the fertilizer is fully dissolved. Water the bonsai before applying the fertilizer. Fill the container to the rim with the fertilizer solution after the soil finishes absorbing the water. Reapply the fertilizer every seven to 14 days, starting in the spring once active growth begins and continuing through midsummer. Reduce applications to once every 14 to 21 days from midsummer to early fall. Stop fertilizing the hemlock in the fall once it enters dormancy.

4

Check the bonsai's leaves periodically for the presence of green-bodied aphids, white waxy mealybugs, round brown scale, spider mite webs and whiteflies. Mix neem oil at a rate of 2 tablespoons per gallon of water in a spray bottle. Spray the infested area of the hemlock thoroughly, coating the harmful pests. Reapply the solution seven to 14 days later if the pests still exist. Do not spray the neem oil solution when the temperature falls below 40 degrees F or rises above 80 degrees F.

5

Repot the Canadian hemlock bonsai in the spring, just before it begins to produce new growth. Slide the plant gently from its container and brush away any loose soil from the roots. Discard any soil remaining in the container. Wash the container in warm soapy water and dry it with a cloth. Trim back the plant's roots by 1 inch with a pair of pruning snips. Cut off any roots with a diameter of 1/4 inch or greater.

6

Mix two parts sand, one part loamy potting soil and one part peat moss in a bucket or container. Add water slowly while mixing the ingredients, stopping once the mixture is damp but not wet. Fill the bottom one-third of the original container with the media, tamping it down slightly. Place the plant in the container, adjusting the soil level as needed to position the root ball's top at its previous growing depth. Fill the container to 1 inch below its rim with additional medium, tamping it down around the roots. Do not overfill the container. Water the bonsai thoroughly. Repeat the repotting process every two years for immature specimens and every three to four years once the bonsai matures.

7

Prune the Canadian hemlock bonsai in midspring after it breaks out of dormancy. Cut off any dead or broken branches using a pair of pruning snips. Make each cut 1/4 inch above the limb's base when removing the entire limb. Cut 1/4 inch above a leaf bud or lateral branch when shortening a limb. Cut back one-half of the hemlock's new growth, shaping the plant as desired.

8

Unwind any wires present on the hemlock's branches at the time of pruning to prevent them from girdling the plant's limbs. Wrap new copper or aluminum wire in coils around the same branches or new branches to train them to grow in the desired direction. Bend the wired branches slightly in the desired direction once wired. Cut through excess lengths of wire with a pair of wire cutters. Bend the wire ends into a loop to disguise them. Repeat this process each year to train the tree.

9

Trim back the bonsai throughout the growing season as needed. Clip back vigorously growing shoots to encourage lateral branching where desired. Cut off side branches as needed to thin out dense portions and allow sunlight and air to penetrate the canopy.